We have characterized a full-length gene that codes for a protein homologous (approx. 40%) to the mitogen-activated protein (MAP) kinase of other organisms. This MAP Kinase homologue, Pfmapk, contains a TXY motif, the dual phosphorylation site unique to MAP Kinases, upstream of the highly conserved VATRWYRAPE sequence in subdomain VIII. Pfmapk also contains an unusually large and highly charged domain (approx. 300 amino acid residues) at its carboxyl terminal segment, which includes a repetitive sequence of tetrapeptides. This highly charged carboxyl terminal sequence has shown limited homology with some merozoite surface antigens such as MESA and MSP-1, suggests Pfmrp-1 may interact with other molecules through this charged domain similar to those merozoite antigen. Sequences from the genomic and cDNA clones indicate a homologue of cyclic GMP-dependent protein kinase (cGK) contains at least 3 introns at its 5' region. The expression of identified protein kinases (MAPK, cGK and casein kinase I) was shown to be developmentally regulated under normal physiological conditions. The activity of each kinase during growth and development will be further examined.We have characterized a full-length gene that codes for a protein homologous (approx. 40%) to the mitogen-activated protein (MAP) kinase of other organisms. This MAP Kinase homologue, Pfmapk, contains a TXY motif, the dual phosphorylation site unique to MAP Kinases, upstream of the highly conserved VATRWYRAPE sequence in subdomain VIII. Pfmapk also contains an unusually large and highly charged domain (approx. 300 amino acid residues) at its carboxyl terminal segment, which includes a repetitive sequence of tetrapeptides. This highly charged carboxyl terminal sequence has shown limited homology with some merozoite surface antigens such as MESA and MSP-1, suggests Pfmrp-1 may interact with other molecules through this charged domain similar to those merozoite antigen. Sequences from the genomic and cDNA clones indicate a homologue of cyclic GMP-dependent protein kinase (cGK) contains at least 3 introns at its 5' region. The expression of identified protein kinases (MAPK, cGK and casein kinase I) was shown to be developmentally regulated under normal physiological conditions. The activity of each kinase during growth and development will be further examined.